This invention relates to control arrangements for hydraulic systems and, more particularly, to such control arrangements as are used to achieve lifting and/or angling of a vehicle mounted snowplow blade.
It is well known to control the hydraulic circuit of a vehicle mounted snowplow blade with a 4-way, open-center, three position valve. The operation of such valves has been controlled through, for example, the use of bowden wires and also with the use of solenoid actuators. The objectives sought in such systems are compactness of the basic operating elements and to minimize the amount of hydraulic tubing and control lines (mechanical and electrical) required, all consistent with effective and reliable operation. In this regard, there has been a growing tendency toward the use of solenoid actuators and away from bowden wires.
This invention is concerned with this general area and has among its general objects to simplify the valve arrangement of the hydraulic system and permit the use of relatively small and yet effective solenoid units in the valve actuator.